Cored slab wall panels

ABSTRACT

Apparatus and method for forming cored concrete panels including providing a two-piece core having the core pieces of complementary wedge shape with one section tapering to a point on the end adapted to be positioned within a panel, a plastic envelope encloses the core pieces, and means connect to the core for inflating the envelope under pressure casting conditions. Additionally, the invention comprises pouring fresh concrete around the envelope enclosed core when it is positioned in a mold, closing the mold and inflating the envelope to force the concrete to fill the mold. After the concrete is set, the core can be removed piece by piece to provide a cored concrete panel with a plastic envelope outlining the core opening.

[15] 3,677,688 1 July 18,1972

[54] CORED SLAB WALL PANELS Burton D. Morgan, 302 Aurora, Stow, Ohio 44236 22 Filed: Sept.4, 1970 21 Appl.No.: 69,541

[72] Inventor:

[52] US. Cl ..425/468, 249/65, 264/314,

249/183, 249/184 [51] Int. Cl. ..B29c 1/12, B28b 7/28 [58] field of Search .18/34 S, 45 R, 45 RR, 46, DIG. l4, 18/D1G. 2, D16. 12, DIG. 44; 25/128 D, 41; 249/65,

2,170,188 8/1939 Cobi ..249/65 2,907,074 10/1959 Rh0deS.... .....264/314 X 3,561,079 3/1968 Anderson ..264/314 X FOREIGN PATENTS OR APPLICATIONS 473,634 10/ 1 937 Great Britain ..249/65 Primary Examiner-Robert L. Spicer, .Tr. Att0rney-Oldham & Oldham ABSTRACT Apparatus and method for forming cored concrete panels including providing a two-piece core having the core pieces of complementary wedge shape with one section tapering to a point on the end adapted to be positioned within a panel, a plastic envelope encloses the core pieces, and means connect to the core for inflating the envelope under pressure casting conditions. Additionally, the invention comprises pouring fresh concrete around the envelope enclosed core when it is positioned in a mold, closing the mold and inflating the envelope to force the concrete to fill the mold. After the concrete is set, the core can be removed piece by piece to provide a cored concrete panel with a plastic envelope outlining the core opening.

6 Claim, 7 Drawing Figures Patented July 18, 1972 3,677,688

FIG. 4

h1g5 g K 54 FIG. 5 56 INVENTOR.

BURTON D. MORGAN ATTORNEYS CORED SLAB WALL PANELS The present invention relates to cored concrete panels, especially to such panels as are adapted to be used for wall, floors, partitions, or other building actions, as desired.

BACKGROUND OF INVENTION l-leretofore there'has been increasing amount of work done in the precasting of concrete structures, and particularly relating to wall panels and other structural elements, although tensioned precast concrete articles of various types have been provided. This invention particularly has to do with low cost, economical production of standarized articles especially adapted for use as wall panels of the like wherein a minimum load carrying capacity is required in the panel.

A number of process and apparatus have been used heretofore commercially to make precast concrete and some typical apparatus for making precast concrete articles includes the apparatus and method disclosed in US. Pats. Nos. 1,480,740; 1,552,064 and 2,650,412.

The general object of the present invention is to provide a novel and improved apparatus and method for making precast concrete structures and to provide such structures by a readily practiced method using improved concrete molding apparatus.

Another object of the invention is to provide a special envelope enclosed two-piece core for use in concrete molding actions and wherein the core has two complementary wedgeshaped sections provided therein with one of the sections tapering to a point on the end thereof adapted to be positioned within a formed concrete panel to facilitate removal of such cored section after the concrete is set.

Another object of the invention is to provide a two-part core enclosed in a plastic inflatable envelope for use in concrete molding or casting actions whereby the envelope can be inflated during concrete curing or setting conditions to facilitate removal of the initial support core present in the apparatus.

Another object of the invention is to use a relatively thin, tough but inexpensive plastic envelope for enclosing a core during concrete setting actions but wherein the core in inflatable during the setting action to separate it slightly from the core and facilitate core removal.

A further object of the invention is to provide a novel, improved relatively rapidly practiced method of forming accurately shaped concrete panels wherein a number of cores can be provided therein and where a core lining means will be retained in the finished cast concrete article.

Reference now is made to the accompanying drawings, wherein:

FIG. 1 is a perspective view of a two-piece core enbodying the principles of the invention;

FIG. 2 is a side elevation, partially in section, of the core of FIG. 1 with an inflatable envelope and associated means operatively assembled therewith;

FIG. 3 is a fragmentary vertical section through a portion of a mold embodying the principles of the invention and showing the molding action provided by the invention;

FIG. 4 is a fragmentary section through a cast concrete panel provided by the invention;

FIG. 5 is a fragmentary perspective view of the panel of FIG. 4;

FIG. 6 is a fragmentary vertical section showing removal of a core piece from a molded concrete panel; and

FIG. 7 is a perspective view of a modified core.

When referring to corresponding members shown in the drawings and referred to in the specification, corresponding numerals are used to facilitate comparison therebetween.

The mold apparatus used in practice of the invention may be of any previously known type, such as the apparatus of the constructions shown in the patents referred to hereinbefore, and the molding apparatus disclosed in my own co-pending patent application Ser. No. 800,418, filed Feb. 19, 1969, also may be used in practice of the invention, if desired.

With reference to the details of the apparatus shown in the drawings, a two-piece core 10 is shown and it is of elongate shape and usually is of generally rectangular shape in vertical section when operatively positioned. The core 10 includes a base piece 12 and an auxiliary top piece 14 with such pieces 12 and 14 being of complementary wedge shape. Specifically, the top piece l4 tapers to a point as indicated at 16 at the end which is adapted to be positioned remote from the processing end or side of the mold in which a concrete panel is to be formed. By this construction, removal of the cores l2 and 14 is facilitated, as hereinafter described. in detail.

Another important feature of the invention resides in the specific association of the core 10 in a concrete panel and the means provided to enable convenient removal of the core from a cast, at least partially set, concrete panel. Hence, FIG. 2 shows that an inflatable envelope 20 is provided to enclose the core 10. This envelope 20 can be made from any relatively inexpensive but tough material, such as a plastic substance of known composition, and the envelope may, for example, be made from a polyethylene or equivalent plastic film which may be as thin as approximately 0.005 inch thick. This envelope 20 is formed of tubular shape and generally corresponds to the size and contour of the core 10. The ends of the envelope 20 can be closed by any suitable means such as by heat sealing such edges together, or by use of metal sealing bands 22 and 24 as indicated in the drawings. The core 10 has fluid transmitting bore means provided therein and a bore or bores 26 is provided extending longitudinally of the base core piece of section 12 and a plurality of vertically extending bores 28, 28 connect to such bore and extend to peripheral portions of the base core piece 12. Hence, any pressure or heat supply or inflation fluid provided to the bore 26 will flow therethrough and through the bores 28, 28 to peripheral portions of the core to inflate or expand the envelope 20 slightly during the molding process, as described hereinafter in more detail.

A suitable pipe or tube 30 connects to one or more of the ends of the bore or bores 26 and it in turn connects to a valve 32 whereby the pipe or tube 30 can be connected to a pressure source by a tube 34 or to a drain by a tube 36.

In the casting of concrete to panel shape, a suitable fixed mold section 40 is provided as a base for the mold and suitable sides are provided for the mold while a vertically movable upper mold section or closure member 42 is provided to complete an enclosure for forming the desired concrete panel. This mold section 42 can be controlled by conventional means for movement to and from association with the upper surface of a mass of freshly poured concrete 44 shown received between the mold sections 40 and 42. Obviously, the envelope enclosed core 10 are positioned in a suitable manner within the cavity formed by the mold base 40 and associated side members (not shown) whereby the freshly poured concrete can be poured into the mold base and substantially surround the cores provided in the mold cavity. Or the cores 10 may be positioned after some concrete is poured into the mold but before it is filled. Usually this freshly poured concrete at least substantially fills the cavity formed by the mold base 40 and upper mold section 42.

After the fresh concrete 44 has been poured into the mold base 40, it can be suitably vibrated, or otherwise processed in a conventional manner as desired. Suitable reinforcements may be added to the concrete, if needed.

It will be realized that any desired known concrete composition can be used for forming concrete panels but that usually some type of concrete setting addative is present in the fresh concrete to facilitate getting a rapid preliminary setting or hardening of the concrete in the mold whereby the concrete panel can be taken from the mold and be allowed to cure completely under any other desired conditions.

It likewise should be realized that the fresh concrete 44 in the mold sections 40 and 42 can be subjected to heat as well as pressure during the molding operation to facilitate getting the preliminary set desired. The pressure tube 34 may connect,

for example, to a source of steam under pressure whereby steam can be caused to flow into the bores in the mold core and press outwardly against the plastic envelope 20 whereby it will uniformly expand and aid in forcing the concrete to fill the mold cavity fully. The plastic envelope 20, in accordance with the teachings of the invention, will be expanded or inflated slightly so as to provide some clearance between the core and the envelope to facilitate removal of the core pieces after the concrete is set. The mold sections 40 and 42 may have heat supplied thereto if desired.

During the concrete setting action, if desired, the previous teachings in the art of applying vacuum forces to the surfaces of the fresh concrete may be used to facilitate withdrawal of any excess water present in the concrete and aid in obtaining the desired preset concrete condition. The steam, hot water, or hot air used to inflate the envelope normally would be under low pressure and temperature conditions, but would aid in driving water out of the concrete and in heating the same without actually causing the water in the concrete to evaporate and form voids therein under the pressure conditions existing.

FIG. 4 of the drawings shows a vertical section of a cast concrete panel 50 provided by the invention. Obviously, the cores 10 used in forming the panel 50 may be of any desired shape to provide, in this instance, substantially rectangularly shaped core openings 52, 54, and 56, etc. therein. These core openings extend completely to one end or side margin of the concrete panel 50 and may extend one full dimension thereof if desired.

Before or after the mold has been opened by lifting the upper mold section 42, the valve 32 would be changed in position so as to drain any pressure fluid from the envelopes 20, and the sealing bands 22 and 24 would usually be removed from the ends of the bores formed in the concrete panel. Then a suitable member, such as a handle or grip 60, would be engaged with a tapped hole provided in the top core piece 14. FIG. 6 shows how this core piece then can be readily slid out of the concrete panel 50. Then a similar handle could be engaged with the core base 12 and it can be drawn from the concrete panel. If desired, the pipe connecting to the core base 12 can be flexible to facilitate movement of such core piece toand from operative positions for the same.

It will be seen that the envelope 20 used in forming the I cores in the concrete panel will remain therein after the concrete has been set but these envelopes are inexpensively formed and usually will be bonded to the concrete panel for movement or shipment therewith and do not present any cost or use problems.

By the present invention, a novel and improved method has been provided for obtaining cored panels of predetermined size and shapes and which panels can be accurately formed. The panels can be relatively light in weight by producing any number and size of voids or cores therein as is desired. Obviously the core 10 can be made in more than two pieces, if desired, but the specific shape shown is believed to be very effective and aids in removal of the core, piece by piece, from the cast concrete. Obviously, other complementary wedgeshaped types of cores can be provided, if desired, to form cylindrical openings or other shapes of openings in a cast concrete panel. The top core piece 14 can be made in other shapes as is indicated by the core 10a of FIG. 7 wherein the core base piece 12a and the complementary core piece l4a each extends the height of the core piece but have complementary wedge-shapes engaging each other as indicated in the drawings. However, by the wedge shape for the top piece 14 of FIG. 1 decreasing gradually in height and not occupying a full core section at any area thereof, the sliding removal action thereof is thought to be facilitated. Obviously, the core pieces are formed from metal members or other suitable, durable material and have low friction sliding contact between the associated wedging surfaces thereof.

While one complete embodiment of the invention has been disclosed herein, it will be appreciated that modification of this particular embodiment o the invention may be resorted to without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. Apparatus for fonning cored concrete panels including a mold and comprising the features of an elongate two-piece core having pieces of complementary wedge shape, and fitting relatively of each other to form a single mandrel, each piece of said core extending the length of each other,

a plastic envelope enclosing said core, and

means operatively connecting to said core for inflating said envelope whereby fresh concrete can be positioned around said plastic envelope as supported by said core in said mold, said envelope can be inflated, and said core be removed piece by piece after the concrete has set.

2. Apparatus for forming cored concrete panels as in claim l and including said core being of generally rectangular shape in section, one core piece tapering to a point on the end thereof adapted to be positioned within a panel.

3. Apparatus as in claim l and comprising said core having bore means formed therein and extending from one end thereof to a remote peripheral portion thereof.

4. Apparatus as in claim 1 where said means includes bore means formed in at least one of said core pieces and extending therethrough from one end thereof to a surface portion thereof, and connection means engaging said one end of said bore means for connection to a fluid pressure supply source.

5. Apparatus for forming cored concrete panels as in claim 1 and including said core being adapted to extend into a panel from one edge thereof and being of generally rectangular shape in section, each part of said core extending the length thereof and with the parts being of complementary shape, one core part tapering to a point on the inner end thereof whereby said one core part can be withdrawn from a relatively wide panel after minimum expansion of said envelope and said second core part can then be removed.

6. Apparatus as in claim 1 and comprising said core being adapted to extend within the mold and to an edge of the panel to be formed, a base of one core piece being positioned at such edge of said panel. 

1. Apparatus for forming cored concrete panels including a mold and comprising the features of an elongate two-piece core having pieces of complementary wedge shape, and fitting relatively of each other to form a single mandrel, each piece of said core extending the length of each other, a plastic envelope enclosing said core, and means operatively connecting to said core for inflating said envelope whereby fresh concrete can be positioned around said plastic envelope as supported by said core in said mold, said envelope can be inflated, and said core be removed piece by piece after the concrete has set.
 2. Apparatus for forming cored concrete panels as in claim 1 and including said core being of generally rectangular shape in section, one core piece tapering to a point on the end thereof adapted to be positioned within a panel.
 3. Apparatus as in claim 1 and comprising said core having bore means formed therein and extending from one end thereof to a remote peripheral portion thereof.
 4. Apparatus as in claim 1 where said means includes bore means formed in at least one of said core pieces and extending therethrough from one end thereof to a surface portion thereof, and connection means engaging said one end of said bore means for connection to a fluid pressure supply source.
 5. Apparatus for forming cored concrete panels as in claim 1 and including said core being adapted to extend into a panel from one edge thereof and being of generally rectangular shape in section, each part of said core extending the length thereof and with the parts being of complementary shape, one core part tapering to a point on the inner end thereof whereby said one core part can be withdrawn from a relatively wide panel after minimum expansion of said envelope and said second core part can then be removed.
 6. Apparatus as in claim 1 and comprising said core being adapted to extend within the mold and to an edge of the panel to be formed, a base of one core piece being positioned at such edge of said panel. 